Device for chasing pests



Oct. 9, 1962 N. R. EVANS 3,058,103

DVICE FOR CHASING PESTS Filed Sept. l0, 1958 mw' 2 Sheets-Sheet 1 o gn g 19" 'Vvw` Q 8 1 )Su N 9 S2 1 Il AA/W -AVAVV-'l a, j

INVENTOR.

\ NORMAN R. EVANS C BY m 'l' ATTORNEYS Oct. 9, 1962 N. R. EVANS DEVICE FOR cHAsING PEsTs 2 Sheets-Sheet 2 Filed Sept. l0, 1958 INVENTOR. NORMAN R. EVANS /Muwd 1PM ATTORNEYS tred Etant 3,@5,l3 Patented Oct. 9, 1962 3,ii5'8,1t3 DEVEE FR QHASNG PESS Norman R. Evans, Cieveiand, t'iiio, assigner of one-sixth to John U. Weiher, Fort Lauderdale, Fia., one-sixth to Ben F. Dellett, Atlanta, Ga., and one-sixth to Mirabeau M. Kraus and one-sixth te Norman E. Yanover, both of Cleveland, hio

Filed Sept. 10, 1958, Ser. No. 7649,133 6 Ciaims. (Si. 34h- 384) The invention relates in general to a device for chasing pests and more particularly to a device for chasing rodents such as rats and bugs such as flies and mosquitoes.

Many devices have been utilized to catch and/ or drive pests, such as rats, from certain areas lbut none have been entirely successful. The instant invention, as applied specifically to rats, has had a great deal of success in ridding predetermined areas of the pests. Broadly stated, the invention has to do with a device and a method for chasing rodents such as rats. It includes the generation of an alternating signal which has a frequency which lies in a range having the lower limit of the range above that discernible by a human being and having the upper limit of the range lying between twenty and thirty-five kilocycles per second. The generated alternating signal is then preferably constantly varied between these limits. The signal which is generated is then amplified suiiicient'ly to drive a .transducer or speaker to produce a sound which is inaudible to the human ear.

Another feature of the invention has to do with the alternate turning of the speaker on and oif. This in combination with the varying of the frequency as referred to above, appears 4to be something which rats are incapable of withstanding, and as a result, they must leave the areas. The action of this device and method is then preferably used in combination with the action of an eX- terminator, for example, in buildings, by stopping up most of the avenues of escape and then by trapping the pests as they leave through other avenues of escape. In the case of bugs such as flies and mosquitoes, the frequency is preferably Varied in a range which extends from the upper range hereinabove mentioned, namely from twenty to thirty-tive kilocycles per secondup to an upper range lying in the order of two hundred kilocycles per second.

The main objects of the invention are therefore to rid a predetermined area of pests; and, important features of the invention have to do with the varying of the frequency within a predetermined range and alternately turning the sound on and olf.

FIGURE l is a schematic view of the electrical circuit which is utilized in producing the alternating signal.

FIGURE 2 is a circuit drawing of a power amplifying system which is utilized to amplify the signal produced from the circuit of FIGURE l; and

FIGURE 3 is the electrical circuit for the transducer or sound output section of the device.

The circuit of the present invention includes generally an audio sine wave generator section 16, a cathode follower section 11, a square wave generator section 12, a power amplifier section 15 and a sound output section i4.

The audio sine wave generating section 10 consists of first and second oscillator tubes l5 and 15 respectively. The tube 15 is provided with a plate 17, a suppressor grid 18, a screen grid 19, control grid 20 and indirectly heated cathode 21. The second oscillator tube 16 includes a plate 23, a suppressor grid 24, a screen grid 2S, a control grid 26 and an indirectly heated cathode 27. The sine wave generator section 1@ also includes a resistancecapacitance tuning circuit 30. The tuning circuit includes capacitors 35, 36, 37, 38 and 39 and resistors 41 and 42. Resistors 46 and 47 of a larger resistance than 41 and 42 may be thrown into the tuning circuit by means of the band switch Sii which throws resistors 41 and 42 out of the circuit. Switch 5u may be referred to as first selective switch means. These resistors are utilized in the event it is desired to obtain a band of frequencies in a higher range. With the use of resistors 41 and 42, it is possible to obtain a frequency in a first range of from above that audible to the human ear (for example, fifteen to eighteen thousand cycles) to about twenty to thirty-five thousand cycles per second. With the use of resistors 46 and 47 it is possible to obtain frequencies in a second range of from the above mentioned upper limit of the rst range to two hundred thousand cycles per second. A motor 53 is provided and is mechanically connected to capacitors 35, 36, 37, 3S and 39 by a mechanical linkage which has been indicated by the dot-dash lines 54. The electric motor 53 is for the purpose of adjusting the capacitors so that a sweep of frequencies is obtained, for example, from eighteen thousand up to twenty-four thousand cycles per second and then the frequencies are decreased back to eighteen thousand and then back up through the range again. It is desirable that the frequency be varied either by sweeping through the range and then back or by sweeping through and then starting at the beginning again. The signal from the plate 17 of the oscillator tube 15 is introduced onto the control grid 26 of tube 16 by a resistance capacitor coupling which includes the capacitor 5d and resistance 57. The plate 17 is connected to the B+ voltage supply through resistor 6G and the screen grid 19 is connected to the B+ voltage supply through resistor 6i and to B- through resistor 62. The proper bias is obtained for cathode 21 by means of an incandescent lamp 65 and a capacitor 66. The cathode 21 and the suppressor grid 18 are directly connected together and this maintains them at the same potential. A negative voltage is fed back to the cathode circuit 21 from the oscillator tube 16 through a potentiometer 68.

The proper bias for cathode 27 of tube 16 is obtained by the resistor 70 and the capacitor 71. The proper voltage for the plate 23 and the screen grid 25 is obtained from the B+ voltage supply through resistors 73 and 74, respectively. The suppressor grid 24 is maintained at the same potential as the cathode 27 by means of conductor 75.

The signal produced by the tuning circuit 30 is fed onto the control grid 20 of tube 15. The amplified signal is taken off of the plate 17 and fed onto the control grid 26 of tube 16. This signal is in turn amplified and taken oif the plate 23 and is introduced into the cathode follower power amplifier section 11. However, a portion of the signal is fed back into the tuning circuit 30 by Way of l resistor 41. A negative voltage is fed back into the circuit of cathode 21 through potentiometer 68 and is primarily for the purpose of stabilizing the oscillator. The magnitude of the negative feedback voltage is also determined by the incandescent lamp 65. A property of this lamp is that it has a positive temperature coeicient, however, it possesses suiiicient thermal inertia so that its temperature is substantially constant at all frequencies. Because of the lamps positive temperature coefficient, the oscillator cannot build up to a value in excess of the tubes handling capacity. This is so because the resistance of the lamp increases with increased current. As a resul-t, the degeneration of the cathode circuit of the first amplifier increases causing less amplilication in the oscillator section. hus the incandescent lamp serves as an automatic amplitude limiter. The potentiometer 68 in theV cathode circuit of the iirst oscillator tube aids in the proper negative feedback voltage.

'Ihe cathode follower section 11 includes a pentode tube 77 having a plate 78, a suppressor grid 79, a screen grid 80, a control grid 81, and an indirectly heated cathode 82.. The plate 7-3 is connected to the B+ voltage supply through resistor 84 and the cathode and suppressor grid are maintained at the same potential by means of conductor 85. Resistors 88 and 89 `are provided in the cathode circuit and are split to provide the necessary cathode bias. The signal from the plate 23 of oscillator tube 16 is applied to the control grid 81 of tube 77 through la capacitor resistance coupling which comprises capacitor 91 and resistor 92. This voltage signal which is -applied to control grid 81 of tube 77 varies the current ow through the tube which in turn varies the voltage across both of the resistors 88 and 89. The output voltage signal is taken out through capacitor 94 which presents a very low impedance over the entire frequency spectrum.

To produce a square wave form, the square wave generator 12 is switched into the circuit by means of switch 97. Switch 97 may be referred to as second selective switch means. With this accomplished, the signal from the plate 23 of the second oscillator tube 16 is fed into the square wave generator and the signal from the square wave generator is then in turn applied to the cathode follower power amplifier section 11. The square wave generator 12 includes a tube 100, having left and right half portions. The left plate, grid and cathode have been indicated by the reference numerals 101, 102 and 103 respectively and the right half plate, grid and cathode portions have been indicated by the reference numerals 105, 106 and 107 respectively. The left plate portion 101 is connected to the right grid portion 106 and is also connected to the right cathode through resistor 109. The sine wave from the second oscillator tube 16 is fed into the square wave tube 100 through resistor 111 Where grid limiting occurs. This is because the current flow through the resistor 111 on the positive half cycles causes the voltage drop across the resistor to oppose the original signal. As this opposing voltage increases with increasing positive signal, clipping occurs. While the grid voltage is independent of cathode plate conduction through the tube, the plate wave form is not. As the grid voltage dips below the cutoff point of the negative half cycles, cutoff limiting occurs in the negative half of the plate and the wave form is flattened. The right half of the tube 100 follows the plate 101 of the left half in this section. The rounded bottom of the wave form is clipped and the resulting square wave is amplified. This wave is taken from the plate 105 and is introduced through switch 97 onto the control grid 81 of tube 77 the same as described hereinabove for the sine wave form.

The power amplifier section 13 includes a voltage amplifier tube 114, an inverter 115, two power amplifier tubes 116 and 117, and an output transformer 118. Terminals 144 and 145 of FIGURE 2 are adapted to be connected to terminals 112 and 113 respectively of FIGURE 1. The voltage amplifier tube 114 includes first and second cathode portions 119 and 120, rst and second grid portions 121 and 122, and first and second plate portions 123 and 124. The inverter 115 includes first and second cathode portions 125 and 126, first and second grid portions 127 and 128, and first and second plate portions 129 and 130. The first power amplifier tube 116 includes a cathode 132, first and second grids 133 and 134, and a plate 135. The second power amplifier tube 117 includes corresponding elements numbered 137-140, respectively. The output transformer includes a primary winding 142 and a secondary winding 143. The signal from the cathode follower 11 is fed onto the grid 121 of the voltage amplifier tube 114 and the signal is taken from the plate 123. The plate 123 is connected to the second cathode portion 120 as well as to the second grid portion 122. The signal from the second plate portion 124 is fed directly onto the second grid portion 128 of the inverter 115. A signal from the first plate portion 123 circuit is fed directly onto the first grid portion 127 of the inverter 115. As a result, the signals applied to grid portions 127 and 1218 are substantialy 180 out of phase with each other and as a result, the signals from plate portions 129 and 130 will be substantially 180 out of phase. The signal from plate portion 129 is fed onto grid 133 of tube 116 and the signal from plate portion 130 is fed onto gnd 138 of tube 117. The signal from plate portions 135 and 140 are transmitted to the primary 142 of the output transformer and serves to energize the same. The power amplifier section is therefore in effect in push-pull power amplifier.

The sound output section 14 includes first, second, third and fourth transducers 161, 162, and 163 respectively, in the nature of loud speakers. These transducers are -all connected in parallel with each other from the output of the power amplifier section 13. Terminals 147 and 148 of FIGURE 2 are respectively connected to terminals 149 and 150 of FIGURE 3. Located in parallel with the transducers is a power dissipating resister 167. Transducer resistors 170, 171, 172 and 173 are provided and are adapted to replace respectively the transducers 160, 161, 162, and 163 in its respective parallel branch of the circuit. This can be accomplished by throwing respectively, the transducer switches 176, 177, 178 and 179. First contact means 182 is located in the circuit in series with the four transducers and/ or their respective resistors. Second contact means 183 is located in series with or in the parallel branch of the power dissipating resistor 167. A drive motor 185 is mechanically connected to the first and lsecond contact means 182 and 183 respectively, by means of a mechanical linkage indicated by the dot-dash line 186. This construction is such that when the first contact means are closed, the second contact means are open and vice versa. This construction is also of the make-before-break type so that before one of the contacts is opened the other is closed. For the sake of a specific example in the commercial embodiment of the instant device herein disclosed, the drive motor 185 is adapted to rotate at four revolutions per minute. During the first of rotation, contact means 182 are open and contact means 183 are closed. In the next 180 of rotation, cont-act means 182 are closed and contact means 183 are open. This continues while the device is in operation. This means that the transducers which were switched into circuit by means of their respective switches (176, 177, 178 and 179) would operate for 71/2 seconds emitting sound and for the next 71/2 seconds the transducers would be olf with the power from the power amplifier 13 being dissipated in the resistor 167 It should be pointed out that in the sound output section 14 there have been shown four transducers connected in parallel. It should be readily recognized that one transducer might be capable of accomplishing a particular job, but in most cases a plurality of transducers are used. In most cases when a plurality of transducers are utilized in a particular installation they are aimed in different physical directions so as to increase the coverage of the device. In the operation of the device the length of time that the transducers are turned on should preferably equal the length of time that the transducers are turned off. The on-time of the transducer is preferably in the range of from five seconds to five minutes. However, this time might be reduced to on the order of one second and might be lengthened to an upper limit of around eight minutes. It is also desirable in the operation of the device that the transducers be on at least long enough for the motor 53 to vary the frequency produced by the oscillator through a com-plete range. In other words, if the oscillator is producing an alternating signal hom between eighteen thousand to twenty-four thousand cycles per second, the transducers should be on at least long enough for this frequency range to `be swept through. The advantage of utilizing the square wave generator is that the range of harmonics is more readily obtained. It will be also appreciated that many wave forms other than a strictly sine or square Wave can be produced with an external resistance-capacitive circuit in combination with the tuning circuit 30. This external resistance-capacitive circuit would be inserted -between the generator and the load.

The turning of the transducers off and on and sweeping the signal which is generated through a range of frequencies appears to produce an effect which rodents are incapable of being able to stand. As a result, the instant device drives the pests from the area where the device is installed, in a very effective manner.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

l. A mechanism for chasing pests including in combination an oscillator for generating an alternating signal having a frequency lying in a range of above that frequency discernible by a human being and two hundred kilocycles per second, means for varying said frequency within said range, a power amplifier system for amplifying the signal from said oscillator, electrical circuit means connecting the oscillator to said power amplifier system, a sound output section comprising a transducer connected to the output of said power amplifier system, a transducer resistor, a transducer switch for selectively throwing said transducer into and out of the circuit while throwing said transducer resistor out of and into the circuit, a power dissipating resistor connected in parallel with said transducer and said transducer resistor, a first on-off switch located in series with said transducer and transducer resistor, a second on-off switch located in series with said power dissipating resistor, means for controlling said first and second onoff switches by closing said first switch while opening said second switch and opening said first switch while closing said second switch.

2. A mechanism for chasing pests including in combination an oscillator for generating a sine wave signal, said oscillator comprising tube means and a resistancecapacitance tuning circuit, electrical circuit means connecting said tube means and said resistance-capacitance tuning circuit together, means for varying the capacitance of said resistance-capacitance tuning circuit, resistance means, said means for varying said capacitance in combination with a first portion of said resistance means varying the frequency output of said oscillator between a first frequency which is above that discernible by a human being and a second frequency in the range of from kilocycles to kilocycles, said means for varying said capacitance in combination with a second portion of said resistance means varying the frequency output of said oscillator between said second frequency and a third frequency on the order of 200 kilocycles, a square wave generator comprising a third tube, electrical circuit means connecting said oscillator and said third tube together to feed said sine wave into said third tube, a cathode follower comprising a fourth tube, electrical circuit means connecting said third and fourth tubes together to feed said square wave into said fourth tube, second yswitch means interposed in said electrical circuit means which lead to and from said square wave generator and in one position permitting said sine wave to be fed into said square wave generator and the square wave output to be fed into said cathode follower, said second switch means in another position causing the square wave generator to be bypassed and the sine wave signal from said oscillator to be fed directly to said cathode follower, a power amplifier system for amplifying the signal from said cathode follower, electrical circuit means connecting said fourth tube to said power amplifier system, a sound output section comprising a transducer connected to the output of said power amplifier system, a transducer resistor, a transducer switch for selectively throwing said transducer into and out of the circuit while respectively throwing said transducer resistor out of and into the circuit, first and second on-off switches located in series with said transducer and said transducer resistor, means for controlling said first and second on-off switches by closing said first switch while opening said second switch at intervals of a duration from one second to eight minutes and opening said first switch while closing said second switch at intervals of a duration of from one second to eight minutes.

3. A mechanism for chasing pests including in :combination an oscillator for generating a sine wave signal, said oscillator comprising tube means and a resistancecapacitance tuning circuit, electrical circuit means connecting said tube means and said resistance-capacitance tuning circuit together, means for varying the capacitance of said resistance-capacitance tuning circuit, resistance means, said means for varying said capacitance in combination with a first portion of said resistance means varying the frequency output of said oscillator between a first frequency which is above that discernible by a human being and a second frequency in the range of from 20 kilocycles to 35 kilocycles, said means for varying said capacitance in combination with a second portion of said resistance means varying the frequency output of said oscillator between said second frequency and a third frequency on the order of 200 kilocycles, a cathode follower comprising a tube, electrical circuit means connecting said oscillator and said cathode follower, a power' amplifier system for amplifying the signal from said cathode follower, electrical circuit means connecting said cathode follower to said power amplifier system, a sound output section comprising a transducer connected to the output of said power amplifier system, a transducer resistor, a transducer svtu'tch for selectively throwing said transducer into and out of the circuit while respectively throwing said transducer resistor out of and into the circuit, first and second on-off switches located in series with said transducer and said transducer resistor, means for controlling said first and second on-off switches by closing said first switch while opening said second switch at intervals of a duration from one second to eight minutes and opening said first switch while closing said second switch at intervals of a duration of from one second to eight minutes.

4. A mechanism for chasing pests including in combination a first device for generating a sine wave signal, said first device comprising tube means and a tuning circuit, electrical circuit means connecting said tube means and said tuning circuit together, means for Varying said tuning circuit, resistance means, said means for varying said tuning circuit in combination with a first portion of said resistance means varying the frequency output of said first device between a first frequency which is above that discernible by a human being and a second frequency in the range of from 20 kilocycles to 35 kilocycles, said means for varying said tuning circuit in combination with a second portion of said resistance means varying the frequency output of said first device between said second frequency and a third frequency on the order of 200 kilocycles, a second device for generating a square wave comprising a tube, electrical circuit means connecting said first device and said second device together to feed said sine wave into said second device, a cathode follower comprising a tube, electrical circuit means connecting said second device and said cathode follower together to feed said square wave into said cathode follower, second switch means interposed in said electrical circuit means which lead to and from said second device and in one position permitting said since wave to be fed into said second device and the square wave output to be fed into said cathode follower, said second switch means in another position causing the second device to be bypassed and the sine wave signal from said first device to be fed directly to said cathode follower, a power amplifier system for amplifying the signal from said cathode follower, electrical circuit means connecting said cathode follower to said power amplifier system, a sound output section comprising a transducer connected to the output of said power amplifier system, a transducer resistor, a transducer switch for selectively throwing said transducer into and out of the circuit while respectively throwing said transducer resistor out of and into the circuit, first and second on-off switches located in series with said transducer and said transducer resistor, means for controlling said first and second on-off switches by closing said rst switch while opening said second switch at intervals of a duration from one second to eight minutes and opening said first switch while closing said second switch at intervals of a duration of from one second to eight minutes.

5. A mechanism for chasing pests including in combination an oscillator for generating a sine wave signal, said oscillator comprising first and second tubes and a resistance-capacitance tuning circuit, electrical circuit means connecting said first and second tubes and said resistance-capacitance tuning circuit together, drive means for varying the capacitance of said resistance-capacitance tuning circuit, first and second resistance means, first selective switch means for alternately throwing said first and second resistance means into said resistance-capacitance tuning circuit, said drive means in combination with said first resistance means varying the frequency output of said oscillator between a rst frequency which is above that discernible by a human being and a second frequency in the range of from twenty kilocycles to thirtyfive kilocycles, said drive means in combination with said second resistance means varying the frequency output of said oscillator between said second frequency and a third frequency on the order of two hundred kilocycles, a square wave generator comprising a third tube, electrical circuit means connecting said oscillator and Said third tube together to feed said sine wave into said third tube, a cathode follower comprising a fourth tube, electrical circuit means connecting said third and fourth tubes together to feed said square wave into said fourth tube, second selective switch means interposed in said electrical circuit means which lead to and from said square wave generator and in one position permitting said sine wave to be fed into said square wave generator and the square wave output to be fed into said cathode follower, said second switch means in another position causing the square wave generator to be by-passed and the sine wave signal from said oscillator to be fed directly to said cathode follower, a power amplifier system for amplifying the signal from said cathode follower, electrical circuit means connecting said cathode follower to said power amplifier system, a sound output section comprising rst and second transducers connected in parallel with each other and connected to the output of said power amplifier system, first and second transducer resistors, first and second transducer switches for selectively throwing said first and second transducers into and out of the circuit while respectively throwing said first and second transducer resistors out of and into the circuit, a power dissipating resistor connected in parallel with said transducers and said rst and second transducer resistors, a first on-off switch located in series with said transducers and rst and second transducer resistors, a second on-o switch located in series with said power dissipating resistor, means for controlling said first and second on-off switches by closing said first switch while opening said second switch at intervals of a duration of from five seconds to five minutes and opening said first switch while closing said second switch at intervals of a duration of from five seconds to five minutes.

6. A mechanism for chasing pests including in cornbination an oscillator for generating a sine wave signal, said Voscillator comprising first and second tubes and a resistance-capacitance tuning circuit, electrical circuit means connecting said first and second tubes and said resistance-capacitance tuning circuit together, drive means for varying the capacitance of said resistance-capacitance tuning circuit, first and second resistance means, first selective switch means for alternately throwing said first and second resistance means into said resistance-capacitance tuning circuit, said drive means in combination with said first resistance means varying the frequency output of said oscillator between a rs't frequency which is above that discernible by a human being and a second frequency in the range of from twenty kilocycles to thirtyfive kilocycles, said drive means in combination with said second resistance means varying the frequency output of said oscillator between said second frequency and a third frequency on the order of two hundred kilocycles, a cathode follower comprising a tube, electrical circuit means connecting said oscillator and said cathode follower tube together, a power amplifier system for amplifying the signal from said cathode follower, electrical circuit means connecting the tube of said cathode follower to said power amplifier system, a sound output section comprising rst and second transducers connected in parallel with each other and connected to the output of said power amplifier system, first and second transducer resistors, first and second transducer switches for selectively throwing said first and second transducers into and out of the circuit while respectively throwing said first and second transducer resistors out of and into the circuit, a power dissipating resistor connected in parallel with said transducers and said -first and second transducer resistors, a first on-off switch located in series with said transducers and first and second transducer resistors, a second on-off switch located in series with said power dissipating resistor, means for controlling said first and second on-off' switches by closing said rst switch whilegopening said,

second switch at intervals of a duration of from one second to eight minutes and opening said first switch while closing said second switch at intervals o ,a duration of from one second to eight minutes.

References Cited in the file of this patent UNITED STATES PATENTS 1,573,367 Arnold et al Feb. 16, 1926 2,414,495 Vang Jan. 21,71947 2,614,183 Moutinho Oct. 14, 1952 2,819,460 Jacobs Ian. 7, 1958 2,922,999 Carlin Jan. 26, `1960 FOREIGN PATENTS 247,171 Switierland Nov. 17, 1947 862,969 Germany Jan. 15, 1953 f-THER REFERENCES Army Engineers Kill Mice with New Sonic Wave, in Washington Times-Herald newspaper, Nov. 30, 1947.

Some Biological Effects of Intense High Frequency Airborne Sound (Allen et aL), Journal of the Acoustical Society of America, vol. 20, No. l, pages 62-65, January 1948, 

